Densovirus Crosses the Insect Midgut by Transcytosis and Disturbs the Epithelial Barrier Function

Densoviruses are parvoviruses that can be lethal for insects of different orders at larval stages. Although the horizontal transmission mechanisms are poorly known, densoviral pathogenesis usually starts with the ingestion of contaminated food by the host. Depending on the virus, this leads to replication restricted to the midgut or excluding it. In both cases the success of infection depends on the virus capacity to enter the intestinal epithelium. Using the Junonia coenia densovirus (JcDNV) as the prototype virus and the lepidopteran host Spodoptera frugiperda as an interaction model, we focused on the early mechanisms of infection during which JcDNV crosses the intestinal epithelium to reach and replicate in underlying target tissues. We studied the kinetics of interaction of JcDNV with the midgut epithelium and the transport mechanisms involved. Using several approaches, in vivo, ex vivo, and in vitro, at molecular and cellular levels, we show that JcDNV is specifically internalized by endocytosis in absorptive cells and then crosses the epithelium by transcytosis. As a consequence, viral entry disturbs the midgut function. Finally, we showed that four mutations on the capsid of JcDNV affect specific recognition by the epithelial cells but not their binding

Towards seed protection using biocontrol strategies

Papier rédigé à l'issue d'un atelier scientifique “ Semences et Biocontrôle” le 2 Octobre 2019 à Paris organisé par le Consortium Biocontrôle et le GIS Biotechnologies Vertes.International audiencePosition paper, fruit des échanges de l'atelier scientifique “ Semences et Biocontrôle” du 2 octobre 2019 à ParisThe French “Consortium public-privé Recherche-Développement-Innovation sur le Biocontrôle” and the “Groupement d’Intérêt Scientifique Biotechnologies Vertes” (GIS BV), both public-private groups, organized a scientific workshop on “Seeds and biocontrol: solutions for tomorrow’s agricultures” on October 2nd, 2019 in Paris. Seed biocontrol is an emerging research topic that could meet economic issues and environmental and societal expectations to reduce the use of chemical farm inputs and adapt agriculture practices to climate change. Seventy-eight scientists, including forty-five from the private sector joined this workshop in order to debate on the most promising research areas to address a successful implementation of biocontrol solutions. They unanimously agreed that effective biological control solutions will result from multidisciplinary approaches and require innovative in plant breeding developments.This article describes the current strengths of French research in an international context around seed and biocontrol and highlights the research priorities between the public and the private sectors, the upmost being transdisciplinarity for the benefit of future agricultures